**Unattended Sparta Mode**
Buy 3 quake boxes. Upgrade them to 140, 120 & 100 - yes, you want them firing a bit weirdly. Then buy gunmen (59). You can spend the rest as you like. Win without you firing a single shot.
It needs direction indicators where the enemies are coming from -> nothing as crass as an arrow, but something in the level visuals. Quite a promising game. I'd work on the balance - easy was easy until one level wiped me out totally.